"Imagine the city of New Orleans closed for four to six months."

Jefferson Parish Emergency Preparedness Director Walter Maestri

Here's why New Orleans is in such danger from Hurricane Katrina (from the Army Corps of Engineers website):



Obviously, if we see anything like the 25-30 foot storm surge that's currently being predicted, water from Lake Ponchartrain (which connects to the Gulf of Mexico via Lake Borgne and the Mississippi River via shipping canals) will be pushed over the protective levees and floodwalls and be captured in the bowl that New Orleans sits in. I've heard reports of possibly 20 feet of water in Bourbon Street. Residents and businesses there have apparently not done much in the way of protecting themselves from flooding, and one can certainly see why that would be: 20 feet puts the water up to the second storey.

As of this moment (about 2am Eastern), it looks as if the storm will strike the Big Easy head on. The damage could be extensive:

On August 28, 1101 AM CDT, the National Oceanic and Atmospheric Administration (NOAA) issued a bulletin predicting catastrophic damage to the city. Effects include at least partial destruction of one out of every two well-constructed houses in the city, damage to most industrial buildings rendering them inoperable, the total destruction of all wood-framed low-rise apartment buildings, and the creation of a huge debris field of trees, telephone poles, cars, and collapsed buildings.

Further predictions are that the standing water caused by huge storm surges will render most of the city uninhabitable for weeks, while the destruction of oil and petrochemical refineries in the surrounding area will spill waste into the flooding, converting the city into a toxic marsh until water can be drained. Some experts say that it could take six months or longer to pump all the water out of the city. Even after the area has been drained, all buildings will need to undergo inspection to determine structural soundness, as all buildings in the city are likely to be at least partly submerged. Damage and subsequent recovery efforts are predicted to cost the city of New Orleans in excess of US$100 billion. [From Wikipedia]

The devastation has been long anticipated [American Public Media, Sept. 2002]:

On a recent evening, a scientist pulls up in the French Quarter. Joe Suhayda takes a plastic rod out of his trunk and he proceeds to show us what could happen the next time a hurricane hits New Orleans.

"OK, this is tool that I have a range rod," explains Suyhayda. "It will show us how high the water would be if we were hit with a Category Five Hurricane."

Which would mean what?

"Twenty feet of water above where we are standing now," says Suyhayda.

Twenty?

A Category Five Hurricane is the most powerful storm on a scientific scale. Suhayda plants the rod on the sidewalk next to a 200-year-old building that's all wrought iron balconies and faded brick and wooden shutters. Every click marks another foot that the flood would rise up this building.

I can't believe you're still going.

"Yeah, still going," says Suyhayda.

Until a couple months ago, Suhayda ran a prominent research center at Louisiana State University. They've developed the most detailed computer models that anybody's ever used to predict how hurricanes could affect this region. Studies suggest that there's roughly a one in six chance that a killer hurricane will strike New Orleans over the next 50 years.

Suhayda is still extending his stick as he describes what he is doing, "It's well above the second floor, just about to the rooftop."

It's hard to comprehend.

"Yes," agrees Suyahada, "it is really, to think that that much water would occur in this city during a catastrophic storm."

Do you expect this kind of hurricane—this kind of flooding—will hit New Orleans in our lifetime?

"Well I would say the probability is yes," says Suyahada. "In terms of past experience, we've had three storms that were near misses—that could have done at least something close to this."

Basically, the part of New Orleans that most Americans—most people around the world—think is New Orleans, would disappear.

Suyhayda agrees, "It would, that's right."

[...]

People have known for centuries that New Orleans is a risky spot — the biggest river in North America wraps around it; and most of the land is below sea level. But researchers say they've been learning just how grave the problem is, only in the last few years. And they say the city and the nation aren't prepared to handle it.

To begin to understand why, we clamber up the levees along the Mississippi River. Our guide is Oliver Houck, who runs the environment program at Tulane University Law School.

Houck describes it, "There's no place in the world that has a levee system that is as extensive as this one—it's a monster system."

Walter Maestri [czar of public emergencies in Jefferson Parish] thinks 40,000 people could lose their lives in the metropolitan area if a hurricane were to hit.

The U.S. Army built this monster system we're standing on. Since the late 1800s, the Army Corps of Engineers has built more than 2,000 miles of high, grassy embankments, along the Mississippi and its branches.

"This levee system is to levees around the world, the way that the Great Wall of China is to walls around the world," continues Houck. "There are other walls and then there is The Wall. There are other levees and then there is The Levee system.

The Army built it because storms over the Mississippi used to cause massive floods. Back in the 1920s, the river gushed over its banks and killed thousands of people and forced a million to abandon their homes.

"It was always thought that the big threat of flooding in New Orleans was the river—and it was—because it flooded regularly," explains Houck. "So we beat flooding by taming the river. The irony of history has been that we—like one of those old citadels in an adventure story— defended ourselves against the enemy that we knew, which was the river, but to the rear and to the flank was this other threat, which we are only now beginning to appreciate, and it may be too late to prevent.

[...]

Maestri says imagine what happens if a huge storm hits just to the east of the city.

"The hurricane is spinning counter-clockwise, it's now got a wall of water in front of it some 30 to 40 feet high, as it approaches the levees that surround the city, it tops those levees," describes Maestri. "The water comes over the top - and first the communities on the west side of the Mississippi river go under. Now Lake Ponchetrain— which is on the eastern side of the community—now that water from Lake Ponchetrain is now pushed on the population that is fleeing from the western side, and everybody's caught in the middle. The bowl now completely fills and we've got the entire community under water, some 20 to 30 feet under water."

Remember all those levees that the U.S. Army built around New Orleans, to hold smaller floods out of the bowl? Maestri says now those levees would doom the city, because they'll trap the water in.

"It's going to look like a massive shipwreck," says Maestri. "Everything that the water has carried in is going to be there. It's going to have to be cleaned out— alligators, moccasins and god knows what that lives in the surrounding swamps, has now been flushed -literally—into the metropolitan area. And they can't get out, because they're inside the bowl now. No water to drink, no water to use for sanitation purposes. All of the sanitation plants are under water and of course, the material is floating free in the community. The petrochemicals that are produced up and down the Mississippi river—much of that has floated into this bowl... The biggest toxic waste dump in the world now is the city of New Orleans because of what has happened."

[...]

New Orleans has protected itself from past floods partly with the levees, but the city also operates one of the biggest pumping systems on earth. There are giant turbines all across town, and every time there's a major rain, they suck up the water and pump it out. [Army Corps of Engineers chief researcher Jay] Combes says that system won't work after a huge hurricane.

"The problem," says Combe, "is that the city's been underwater. And the whole city has to be drained by the pumps, and since the pumps have been under the water, the pumps are flooded. They don't operate now— we have to get the pumps back in operation and in order to get the pumps back in order, we have to get the water out of the city."

Sounds like a Catch 22.

"That's correct."

[...]

Researcher Jay Combe has reached a troubling conclusion. He's told his supervisors at the Army Corps of Engineers that if The Hurricane hits New Orleans, most of the buildings in the city would probably be destroyed. If the water didn't demolish them, the hurricane's horrific winds would. And Combe says that raises a question: How many people would die?

Some researchers say 40,000. Some say 20,000. This Army Corps researcher says those figures are probably too low.

Combe worries, "I think of a terrible disaster. I think of 100,000."

That's anywhere from 20,000 to 100,000 deaths from a category 5 hurricane hitting directly on New Orleans. (By way of comparison, the estimated death toll from the Indian Ocean tsunami is around 230,000.)

[Note: As of 3am Eastern, Katrina has been downgraded to a strong category 4 storm, with sustained winds of 155 mph (just under the limit to be considered a category 5 on the Saffir-Simpson scale).]

There's more on the potential impact to New Orleans from a major storm here:

The Mississippi River delta's flat, buckling geography makes it uniquely vulnerable to hurricanes, which destroy with wind, rain, tornadoes and a tidal wave known as storm surge. High winds account for most hurricane damage elsewhere. Louisiana is vulnerable to both winds and floods. When a giant storm surge hits the shallows near the shoreline, the only direction the water can move is up. Like water sloshing against the wall of a bathtub, a storm surge running into a steep, solid coast rises suddenly, then dissipates. Along a gradual slope like the Mississippi River delta's, the surge doesn't rise as high but can penetrate dozens of miles inland.

[...]

The problem for south Louisiana is that the natural protections are rapidly deteriorating, and that in turn is weakening man-made defenses, mainly because the entire delta region is sinking into the Gulf of Mexico. The Louisiana coast resembles a bowl placed in a sink full of water. Push it down, or just tip it slightly, and water rushes in.

[...]

If enough water from Lake Pontchartrain topped the levee system along its south shore, the result would be apocalyptic. Vast areas would be submerged for days or weeks until engineers dynamited the levees to let the water escape. Some places on the east bank of Orleans and Jefferson parishes are as low as 10 feet below sea level. Adding a 20-foot storm surge from a Category 4 or 5 storm would mean 30 feet of standing water.

Whoever remained in the city would be at grave risk. According to the American Red Cross, a likely death toll would be between 25,000 and 100,000 people, dwarfing estimated death tolls for other natural disasters and all but the most nightmarish potential terrorist attacks. Tens of thousands more would be stranded on rooftops and high ground, awaiting rescue that could take days or longer. They would face thirst, hunger and exposure to toxic chemicals.

"We don't know where the pipelines are, and you have the landfills, oil and gas facilities, abandoned brine pits, hardware stores, gas stations, the chemicals in our houses," said Ivor van Heerden, assistant director of the LSU Hurricane Center. "We have no idea what people will be exposed to. You're looking at the proverbial witch's brew of chemicals."

[...]

With computer modeling of hurricanes and storm surges, disaster experts have developed a detailed picture of how a storm could push Lake Pontchartrain over the levees and into the city.

"The worst case is a hurricane moving in from due south of the city," said Suhayda, who has developed a computer simulation of the flooding from such a storm. On that track, winds on the outer edges of a huge storm system would be pushing water in Breton Sound and west of the Chandeleur Islands into the St. Bernard marshes and then Lake Pontchartrain for two days before landfall.

"Water is literally pumped into Lake Pontchartrain," Suhayda said. "It will try to flow through any gaps, and that means the Inner Harbor Navigation Canal (which is connected to Breton Sound by the Mississippi River-Gulf Outlet) and the Chef Menteur and the Rigolets passes.

"So now the lake is 5 to 8 feet higher than normal, and we're talking about a lake that's only 15 or 20 feet deep, so you're adding a third to a half as much water to the lake," Suhayda said. As the eye of the hurricane moves north, next to New Orleans but just to the east, the winds over the lake switch around to come from the north.

"As the eye impacts the Mississippi coastline, the winds are now blowing south across the lake, maybe at 50, 80, 100 mph, and all that water starts to move south," he said. "It's moving like a big army advancing toward the lake's hurricane-protection system. And then the winds themselves are generating waves, 5 to 10 feet high, on top of all that water. They'll be breaking and crashing along the sea wall."

Soon waves will start breaking over the levee.

"All of a sudden you'll start seeing flowing water. It'll look like a weir, water just pouring over the top," Suhayda said. The water will flood the lakefront, filling up low-lying areas first, and continue its march south toward the river. There would be no stopping or slowing it; pumping systems would be overwhelmed and submerged in a matter of hours.

"Another scenario is that some part of the levee would fail," Suhayda said. "It's not something that's expected. But erosion occurs, and as levees broke, the break will get wider and wider. The water will flow through the city and stop only when it reaches the next higher thing. The most continuous barrier is the south levee, along the river. That's 25 feet high, so you'll see the water pile up on the river levee."

As the floodwaters invade and submerge neighborhoods, the wind will be blowing at speeds of at least 155 mph, accompanied by shorter gusts of as much as 200 mph, meteorologists say, enough to overturn cars, uproot trees and toss people around like dollhouse toys.

The wind will blow out windows and explode many homes, even those built to the existing 110-mph building-code standards. People seeking refuge from the floodwaters in high-rise buildings won't be very safe, recent research indicates, because wind speed in a hurricane gets greater with height. If the winds are 155 mph at ground level, scientists say, they may be 50 mph stronger 100 feet above street level.

Buildings also will have to withstand pummeling by debris picked up by water surging from the lakefront toward downtown, with larger pieces acting like battering rams.

Ninety percent of the structures in the city are likely to be destroyed by the combination of water and wind accompanying a Category 5 storm, said Robert Eichorn, former director of the New Orleans Office of Emergency Preparedness. The LSU Hurricane Center surveyed numerous large public buildings in Jefferson Parish in hopes of identifying those that might withstand such catastrophic winds. They found none.

Amid this maelstrom, the estimated 200,000 or more people left behind in an evacuation will be struggling to survive. Some will be housed at the Superdome, the designated shelter in New Orleans for people too sick or infirm to leave the city. Others will end up in last-minute emergency refuges that will offer minimal safety. But many will simply be on their own, in homes or looking for high ground.

Thousands will drown while trapped in homes or cars by rising water. Others will be washed away or crushed by debris. Survivors will end up trapped on roofs, in buildings or on high ground surrounded by water, with no means of escape and little food or fresh water, perhaps for several days.

"If you look at the World Trade Center collapsing, it'll be like that, but add water," Eichorn said. "There will be debris flying around, and you're going to be in the water with snakes, rodents, nutria and fish from the lake. It's not going to be nice."

Mobilized by FEMA, search and rescue teams from across the nation will converge on the city. Volunteer teams of doctors, nurses and emergency medical technicians that were pre-positioned in Monroe or Shreveport before the storm will move to the area, said Henry Delgado, regional emergency coordinator for the U.S. Public Health Service.

But just getting into the city will be a problem for rescuers. Approaches by road may be washed out.

[...]

Stranded survivors will have a dangerous wait even after the storm passes. Emergency officials worry that energized electrical wires could pose a threat of electrocution and that the floodwater could become contaminated with sewage and with toxic chemicals from industrial plants and backyard sheds. Gasoline, diesel fuel and oil leaking from underground storage tanks at service stations may also become a problem, corps officials say.

A variety of creatures -- rats, mice and nutria, poisonous snakes and alligators, fire ants, mosquitoes and abandoned cats and dogs -- will be searching for the same dry accommodations that people are using.

Contaminated food or water used for bathing, drinking and cooking could cause illnesses including salmonella, botulism, typhoid and hepatitis. Outbreaks of mosquito-borne dengue fever and encephalitis are likely, said Dr. James Diaz, director of the department of public health and preventive medicine at LSU School of Medicine in New Orleans. [More]

It all sounds distressingly apocalyptic -- but we all may be affected in some way:

Crude-oil and natural-gas prices may soar after Hurricane Katrina moved into production regions of the Gulf of Mexico, forcing companies including Exxon Mobil Corp. and Chevron Corp. to close operations.

Royal Dutch Shell Plc said it shut 420,000 barrels of daily oil production in the Gulf. The Louisiana Offshore Oil Port, which handles about 11 percent of U.S. imports, closed yesterday. Katrina is one of the most powerful storms ever to enter the Gulf, source of about 30 percent of U.S. oil production and 24 percent of the country's natural gas.

``Forecasters are saying Katrina could do more energy damage than any storm in recent years,'' said Jason Schenker an economist with Wachovia Corp. in Charlotte. ``It's not just that there's going to be outages for the next couple of days. With shutdowns and damage at platforms and refineries, the bullish impact could be felt for the rest of the year.''

[Bloomberg News]

That probably means higher gas prices, perhaps fairly quickly, especially if refineries have to be shut down as well.

As I sit here, at home in my little apartment in Manhattan, and watch the wall-to-wall coverage of Katrina on cable TV, the feeling is something like the one I felt during the lead-in to the war in Iraq, as we got closer and closer to what was obviously going to be a long-term disaster about which I could do nothing.

Update (9:10am): CNN is reporting that part of the roof of the Superdome in New Orleans, where about 10,000 people are sheltered from the storm, has opened up. A local reporter said that he could see daylight through a section of the roof that was about 1/12th of the entire circumference.

There is, of course, no chance of doing anything about it.

(10:10am): I've heard reports of water going over at least one levee in New Orleans, but no indication of how much or where. The only specific report concerned a canal near Tennessee Street, which I think might be the slanted canal below the north-south canal to the left of center of the map below (near where it says Claiborne St.):



There have also been reports of "total structural damage" to buildings, but I haven't heard these confirmed by anyone on the scene. Brian Williams of MSNBC is reporting "many many holes" in the Superdome roof with "a whole lot of water" coming in, but no indication that the roof is going to fail catastrophically.

In any event, the eye of the storm seems to be passing to the east of the city, and the predicted storm surge in Lake Ponchartrain seems like it will be under 15 feet. Since I believe the levees and floodwalls protecting the city vary from 13-20 feet, it'll be close. The city is already flooding, but from the rain and not (as far as I've heard) from water from the lake or the Mississippi River.

It looks like perhaps Biloxi and Gulfport in Mississippi will be hardest hit.

(11:30am):

AP: The National Weather Service reported that a levee broke on the Industrial Canal near the St. Bernard-Orleans parish line, and 3 to 8 feet of flooding was possible. The Industrial Canal is a 5.5-mile waterway that connects the Mississippi River to the Intracoastal Waterway.

[This is probably the same canal I indicated above; see "I.H.N.C." on the map below. - Ed]

Note: The Army Corps of Engineers district website seems to be unavailable, possibly because of power outages in the area, so I've copied the graphics in the post above to my own storage and adjusted the URLs.

Postscript: There's not a lot that's humorous about a natural disaster such as Katrina (especially when its effects have almost certainly been exascerbated by human denial or neglect of serious problems, as illustrated above) but this is amusing, and illustrates why so many of us have such profound respect for Faux News.

Update Tues 2:30am: This is not amusing in any way. CNN just had a live interview with someone from Tulane University Hosptal, who said that the water there was rising at the rate of 1 inch every 5 minutes (which is 1 foot per hour), and that the rate was increasing over time. In fact, every report I've seen from inside New Orleans has said that the flood water there is rising, hampering rescue efforts.

Much more seriously, the woman reported that the Louisiana State Police confirmed that there is a 2 block long breach on the Orleans Parsh side of the levee at the 17th Street canal. That levee is there to hold back the water of Lake Ponchartrain, but she described water pouring down Canal Street so fast that it had whitecaps.

Water from the lake flooding the city is clearly one of the major components of the nightmare scenarios I posted above.

This is not good.

[This link should bring you to a Google Map which shows Tulane University Medical Center, where I believe the woman was reporting from, and the 17th Street Canal -- which is the thin north-south strip of blue in the center top of the map, just to the west of Ponchartrain Blvd. Canal Street goes northwest of the hospital, and if the water is streaming down it, it might be that the breach in the levee is somewhere near the Lake Lawn Park Cemetary, which can be seen almost in the direct center of the map. This is speculation, of course.]

Note: Any additional updates will be attached to this post.

[More Katrina posts]